How do secured fields behave when records are shared?

A user with access to a secured field in a record can choose to share it with another user or team. The user gives only the access that they have on the record. For example, to share the record and for grant update privileges, the user must have update privileges. You can share a secure field on a particular record with read and/or update with a security principal (User or Team). The user or team member with whom the record was shared now have that type of secured field access only on the shared security fields on only that particular record, even if the user or team member to whom it was shared doesn’t have field security profile that give them access.