The details of the contact added like the name, contact details and so on can be edited if you have the correct permission.

To edit the client details

Step 1: Go to clients in the side navigation bar

Step 2: Select Clients or prospects

Step 3: From the list select the contact whose details are to be edited and click on the three dots at the right end.

Step 4: Select edit from the drop-down.

Step 5: You can also edit contacts by going directly to their profile and selecting the edit icon 

Step 6: The edit page will appear and you can make necessary changes and select save