PDF fillable form fields show up - signature field does NOT. Tried the same forms on iPhone and iPad - they work fine. Can see the "sign" icon under the comments dropdown, but it is greyed out - why?
On android devices open the file in Acrobat Reader DC app. Then click on Viewer on the top left. From the navigation panel select Fill & Sign option and sign the document by tapping at desired location on the document.
On android devices it won't show the Signature field.