It prompts for some sites (using some .well-known URL protocol?). But I recently learned you can add the "One Time Password" field type to any Login entry manually. I do it all the time for intranet/test sites that need MFA and I have done it with sites that didn't prompt that are shared in our family (home) and team (work) 1Password vaults. The field time lets you scan a QR code or enter the seed key manually