Scroll through your Google Drive until you find a document that you want to share with someone. It's to the right of the document. A menu will appear. On Android, tap and hold the document that you want to share. This option is in the menu. Doing so prompts a new window. Tap the "People" field near the top of the page, then enter an email address. This pencil-shaped icon is on the far-right side of the email field. A drop-down menu will appear. Tap one of the following:   Edit or Can edit - The person with whom you share the document will be able to edit the document.  Comment or Can comment - The person with whom you share the document will be able to leave comments about the document, but not edit the document.  View or Can view - The person with whom you share the document will only be able to view, but not edit or comment on, the document. If you want to include a message with your shared document, tap the "Message" text field and then enter the message that you want to include. It's in the top-right corner of the screen. Your document will be shared via email.

Summary:
Find a document that you want to share. Tap ⋯. Tap Add people. Enter an email address. Tap "Edit" . Select a sharing option. Enter a message. Tap "Send" .