As per title really.
1Password Version: 7.3.1Extension Version: 7.3.1OS Version: OS X 10.14.5Sync Type: iCloud
Use the Get_Safari12_Passwords app in the converter suite. It will export the passwords in a format you can then use with the csv converter to convert that export into a 1Password importable 1PIF file.
See the README.html file and the ConvertSafariPasswords.mp4 video where you find the converter suite, in the Extra Help > Screenshots and Samples folder.
The macOS keychain is a tricky one and we don't have anything directly integrated into 1Password for Mac that will help. That said there is a user who likes to inhabit the forum and help other users and he has created a tool that helps with a staggering number of different data sources one of which is the macOS keychain. If you're wondering why I keep mentioning that it's how Safari stores the safely the passwords. You can learn more about this converter from the thread Moving to 1Password from another password manager and from a separate thread on this same topic I can see that MrC even has a video specific to exporting Safari sourced credentials. MrC is friendly and approachable but please do bear in mind he is just another user so he's only here out of the goodness of his heart and is unable to assist with anything that might require a member of 1Password e.g. 1Password account specific queries.
I hope that helps.