You can use your work history to build on your portfolio to establish the credibility clients are looking for in a freelancer.
To add your work history to your profile
Feel free to include student jobs, internships and volunteer experience. You can also include clients and projects from your freelance career outside Upwork. Your Upwork contracts will appear in your work history automatically.
Your employment history will always appear in chronological order, with the most recent at top. Generally, you only need to list the history relating to the types of projects you seek on Upwork. If you have had an unusual combination of jobs, consider adding some of them. It can make you stand out when a client needs experience in a particular field.