If you're just donating the quilt as an individual, it's up to you whether you want to add a label. If you're donating through an organization, check their rules. Sometimes they even provide the labels.
Some people think that every quilt should have a label, and that it should contain every piece of information about the quilt. I don't belong to that group, but I do put labels on quilts that I give to family members. Utility quilts - not so much. And I don't advocate putting any personal information on a quilt that goes to a service organization.