You are able to access Google Docs, Slides, Sheets, or other files stored on your Google Drive and upload them into your sendout. When drafting a sendout, simply click on the Google Drive block.
Choose the document or file you want to upload and it will begin to be added to the sendout. GetAccept will convert it to a PDF, so it will not be able to be edited once uploaded.
If you would like to make edits to your Google Doc, Slide, or Sheet, you can create Google Doc templates and make inline edits while drafting your sendouts.