Sharing data with a clinic works for the most part exactly like sharing data with a person. However, instead of using an email address, the sharing relationship is initiated with a share code: a randomly generated sequence of 12 alphanumeric letters from the set ABCDEFGHJKLMNPQRSTUVWXYZ23456789, in 3 groups separated by dashes like XXXX-YYYY-ZZZZ. Note that the letters I and O, and the digits 0 and 1 are excluded to reduce ambiguity.
The other difference is that sharing data with a clinic grants access to all members of that clinic, rather than individual clinicians.