There are a few ways to achieve this:

1. CRM > Reports > Jobs.

You can type in a client's name in the search field to bring up all the jobs done for them, and then Download CSV.

2. Jobs > View Jobs.

Enter the client's name into the search field, and then click Export.

3. CRM > Contacts > Select edit arrow for specific client > Jobs in the Activity panel.

You can simply click Export in the smart table.