Every step below is from an official source
Switch from Google Password Manager to Bitwarden
What to do at Google Password Manager before you leave, what Bitwarden needs when you join, and everything else the switch touches. Your full plan is built in your browser and stays there.
Official sources reviewed . How we review sources
At Google Password Manager, before you leave
Export passwords from Chrome on a computerBefore
In Chrome, go to More > Passwords and autofill > Google Password Manager > Settings. Scroll to Export passwords and select Download file.
Delete the exported password fileAfter
If you don't delete the password file, anyone who uses the device can open it and see your passwords.
At Bitwarden, when you join
Import from LastPass, 1Password, Chrome and moreDuring
Bitwarden supports imports from common password managers, including LastPass, 1Password, Firefox, Chrome, Edge, Chromium, Password Safe and other Bitwarden vaults.
Import to your vault or collectionsBitwarden Help Center. ReviewedImport LastPass directly, then add attachments by handDuring
Bitwarden's browser extensions and desktop apps can import your individual LastPass vault directly, with no file upload. File attachments and trash must be uploaded to your vault by hand.
Import from LastPassBitwarden. ReviewedSplit files with more than 40,000 itemsBefore
An imported file can contain up to 40,000 items. If your file is too large, split it into smaller files and import each one.
Import to your vault or collectionsBitwarden Help Center. ReviewedDelete the export file after importingAfter
Once your data is in Bitwarden, delete the exported data file from your computer.
Import to your vault or collectionsBitwarden Help Center. Reviewed
Then: everything else the switch affects
The steps above are what Google Password Manager and Bitwarden say. Your full checklist adds the accounts, codes, payments and devices that depend on your password manager, in a safe order. It's built from your answers, in your browser.