vision of progress by the client

I don't understand or I didn't see one thing:

For example :

I manage several independent projects for different clients. as you can give them access to their project as a "visitor" without them being able to modify an element but so that they have a view of the progress and by being able, for example, to make tickets for possible requests, any possible anomalies? 
 
Thanks a lot 

Sylvain