Use your Identity Provider credentials to login into Bitbucket account from any Git Client like SourceTree, GitKraken, etc.
You can use Azure AD, Okta, Keycloak IDPs or any external directory like AD/LDAP to authenticate user against your client.
Our product Git Authentication is available for Atlassian Server and Atlassian Data Center products.
Setup Guides for Git Authentication
You can check our setup guidelines for Bitbucket Git Authentication on this page.