I have a Google document in Drive that I need to share with someone who doesn't haven't a Google account.
Is it possible to share it via anyone with the link can view / edit, but also set a password separately so when they click through the link they need to enter the password to actually view or edit the document?
That is not a feature included in Google Docs nor Google Drive.
If the file was saved using a third-party app (non-Google) and then uploaded to Google Drive, depending on that app, it may support the ability to set passwords.
For example, Microsoft Office and Adobe Acrobat Professional (as well as many other PDF sites and tools) support password protecting files.
If using Google Workspace apps, you could leverage Google Apps Script to restrict the ability to view the document without a password.
