You can add digital signature in the app an then apply it to your scanned documents.
In order to add a signature - tap on a scan to open it on the screen and then tap pen-like button in the low left corner of the screen:
This will open Edit menu where you will be able to see various options. Sign option is the last to the right (see a screenshot):
Tap it and then tap Signature button - you will be forwarded to the next screen, where you need to create a signature by simply signing the screen of you device:
Tap Done when finished and the signature will be added to your app’s signature library:
Now you will be transferred to your scan where you will see the signature:
Move the box around the document for the correct placement of the signature. After this simply tap anywhere outside of the signature box and you will see the document with a signature added.
To move the signature - from the Library quickly double tap the scan to access Editing, then tap the pen-like button and then the Signature button. Done this tap on the signature once to activate the box around it and then move it around the document until reached the necessary position.
Tap the X button in the top left corner of the box in order to Delete the signature: