@June Dowdy If their name is in blue, it is a link to contact them. You can message them through FamilySearch messaging and/or some will have their email available or other contact info for the public to view and use.
also note - even though the messaging system is working just fine - there may be reasons your attempts to contact the other user may not always be succeful - and doesnt necessarily mean you are being ignored
a) the person may be deceased
b) the person may not be a regular active user of FamilySearch
c) The person may have a user account or email that has been deactivated or left unused.
but hopefully they do respond.
if their user id is indicative of their name - you also might wish to use other services to try and locate them - such as google, facebook or Linkedin.
what family were you looking at? I put in entries of a Kelley family
"Send" the User/Patron, that you have found, a 'Message' in/through "User Messaging" of 'FamilySearch'.
Just 'select' their "Contact Name" ANYWHERE you know it is; and, from the resulting "Pop-up" (ie. "Modal") 'Window'; then, go down to the bottom, 'select' the "Send a Message" link ...
User with few details ...
User/Patron with much details ... including an "E-mail" Address ...
[ Where you can even send them an "E-mail" ... ]
Here is a "Knowledge Article" in 'FamilySearch':
How do I send a message to someone who contributed to Family Tree or Memories?
That said ...
Just to give you a 'Heads Up' ...
Please be aware that we DO NOT always get responses to a 'Messages' in/through "User Messaging" of 'FamilySearch' (or, even, direct, "E-mails") that we send.
Sometimes, there is NO response ...
There are many reasons for NO response:
[ some; but, NOT limited to ... ]
▬ has Died/passed away themselves
▬ is not aware of; and/or, does not know how to use,
... "User Messaging" of 'FamilySearch' (and, for some "E-mails")
▬ is an infrequent User/Patron of "Family Tree" of 'FamilySearch'
▬ may have STOPPED using "Family Tree" of 'FamilySearch'
▬ may simply choose NOT to respond
I hope this helps.