You are certainly allowed to ask for exclusive rights to the artwork, although it is unnecessary to do so.
Upwork's default contract is VERY clear. Clients obtain all rights to the work that they pay for.
Unless you and the freelancer create a separate additional contract or agreement, then it is Upwork's default contract that is in effect.
Are you allowed to sell prints of the artwork?
Do you need to include the artist's name or give the artist credit?
Learn more about our awesome Community member Andrei!Learn More
Over the next few weeks you may notice changes to Job Search filters that include the option to filter jobs by an hourly rate range and filter for jobs requiring multiple freelancers.Learn More
We are excited to share a new offering to enable freelancer job referrals (beta). This will provide the option to refer another freelancer on Upwork when you decline a job invite.Learn More
Having a professional profile is essential to attracting clients, highlighting your skills, and winning projects. Come and learn how to make your profile stand out on Upwork!Learn More