It is possible to share a secret without storing it in a vault first

Hi there @gpiepenb

Based on what you've said, I'm assuming (perhaps incorrectly) that you're using a 1Password Business or Teams account. If that's the case, you can invite the external user as a Guest: Share with guests in your team

(1Password Families accounts also support guests: Share with guests in 1Password Families)

You could add whatever items they need to a specific vault, then share only that vault with them. Then, when they don't need those items any more, you can revoke their access to that vault or completely remove them as a Guest.

If you're thinking of something else, let me know what you're aiming to achieve in as much detail as you can and I'll help you work towards a solution. :)

— Grey