Tap and hold any of the icons with an arrow at the bottom to reveal additional options. Many of the below functions are grouped. The icon for whichever function you used most recently in your current session will display. 

Please note that if an item on the Annotations toolbar is highlighted, you won't be able to swipe to the next page—your finger will instead add the selected annotation to the page. Tap the menu option again to deselect it; you can then turn pages using your finger. 

Text Formatting OptionsTap and hold to reveal the additional options
HighlightingTap the highlight icon, and then drag your finger over the text you'd like to highlight. Tap the highlighted text to apply custom color and opacity options.
UnderlineTap the underline icon, and then drag your finger over the text you'd like to underline. Tap the underlined text to apply custom color and opacity options.
Squiggly underlineTap the squiggly underline icon, and then drag your finger over the text you'd like to underline. Tap the underlined text to apply custom color and opacity options.
StrikethroughTap the strikethrough icon, and then drag your finger over the text you'd like to apply a line to. Tap the text to apply custom color and opacity options.
Insert Text OptionsTap and hold to reveal the additional options
Insert free textThis command enables you to type text onto the page. Tap the icon, then tap the spot on the page where you want the text to go. Tap a text box to open the Inspector, which will enable you to customize the color, background, and font.
Insert bordered text boxThis differs from the above function in that it enables to you to type in a bordered box with an attached arrow. Tap a text box to open the Inspector and customize the colors, font, opacity, etc.
Insert signatureYou can save your signature to use again or add a one-time signature. Once it is placed, you can adjust the size of the signature by tapping it and dragging the corners inward or outward.
Insert noteTap the note icon, then tap on the page where you'd like to insert the note. Type your note in the box, and then tap Edit to customize the note's shape and color. 
Pen toolThis is an ink tool that lets you draw freehand. Customize the color, thickness, and opacity of the pen by tapping on the color icon that displays when the pen tool is selected. There are two pen tools on the menu bar, allowing you to switch back and forth quickly between two commonly used color and width settings.
Insert ShapesTap and hold to reveal the additional options 
ArrowSelect the arrow icon and drag your finger across the page to create an arrow. Select an arrow you've placed to get to the inspector, which enables you to customize the color, opacity, line thickness, and arrow end and start shapes. Use the blue dots on a selected arrow to change its length and direction. 
LineSelect the line icon and drag your finger across the page to create a line. Select a line you've placed to get to the inspector, which enables you to customize the color, opacity, line thickness, and line end and start shapes. Use the blue dots at the ends of a selected line to change its length and direction. 
RectangleSelect the rectangle icon and drag your finger across the page to create a rectangle. Select a rectangle you've placed to get to the inspector, which enables you to customize the border and fill colors, opacity, thickness, and border style. Use the blue dots on a selected shape to change its shape and size. 
EllipseSelect the ellipse icon and drag your finger across the page to create an ellipse. Select an ellipse you've placed to get to the inspector, which enables you to customize the border and fill colors, opacity, thickness, and border style. Use the blue dots on a selected ellipse to change its shape and size. 
PolygonSelect the polygon icon and drag your finger across the page to create the first edge of the shape. Continue to swipe to create additional sides until you've joined with the first line. Select a polygon you've placed to get to the inspector, which enables you to customize the border and fill colors, opacity, thickness, and border style. Use the blue dots on a selected shape to change its shape and size. 
PolylineSelect the polyline icon and drag your finger across the page to create a line. Continue to swipe to create additional lines. Select a set of lines you've placed to get to the inspector, which enables you to customize the color, opacity, thickness, and line start and end shapes. Use the blue dots on a selected group of lines to change the angles and lengths of the lines. 
Images and SoundTap and hold to reveal the additional options.
Image annotationsYou can add an image either by taking a picture with your camera or by pulling from your photo library. Tap the image icon, then select Camera or Photo Library. You can crop the image before placing it. Once placed on the page, change the position and size by dragging one of the blue dots around the outside of the picture. You can add an associated note if desired. 
Sound recordingsTap the microphone icon, then tap on the page where you'd like the audio note to go. When you're ready to record, tap the red circle, then tap the blue square to stop recording. You can move the audio note by dragging the audio note's speaker icon elsewhere on the page. Select the speaker icon of an existing note to play, add a typed note, or delete the recording.
Stamps

Selecting the stamp icon will give you a menu of pre-designed stamps such as "Approved," "Final," "Draft," "Void," "Sign here," etc. Tap the selected stamp and then place it on the page. You can resize if desired and add a note. 

You can also save annotations using the Stamps function. After you tap the stamp icon, select Saved Annotations at the top of the stamp menu. You can paste copied annotations here if you have customized something that you'd like to use again in the future. Copy the annotation by tapping it and selecting copy, then paste here by tapping Paste at the bottom of the Saved Annotations menu.

EraserThe eraser is used to remove portions of a line drawn using the pen tool. Tap the eraser and drag it over the portion of the ink you'd like to delete. Note: the eraser does not erase shapes, formatting, or lines. To delete these annotations, select them and then tap the trash can icon.
Multi-select toolYou can use this tool to select annotations you'd like to edit or delete. Tap the icon and then drag your finger over the annotation you'd like to select. You can also select multiple items and batch delete or group them so that they'll move and be resized as one unit. 
UndoTap this icon to undo the last annotation. Each subsequent tab will undo the next most recent markup. 
RedoTap this icon to redo an annotation that has been undone using the undo icon. Each subsequent tap will redo the next most recent undone action.
CloseTap the x icon to close the Annotations toolbar. You can open it again at any time using the annotation icon on the main toolbar.
Move menuTap and drag this icon to move the Annotations menu to either side or the top of the screen. The menu will display vertically when placed at either side and horizontally when placed at the top.