Don't think you can—profile needs to be set up using a web browser. The mobile app, as far as I understand it, is for perusing job postings, veiwing invitations, and messaging clients.
Are you having any particular issue or error when completing your profile? Can you try using a different browser and let us know if the issue persists?
Same problem here. I can't create a profile coz what shows is just a text saying
Welcome to Upwork! Tell us about the type of work you're interested in.
Even how many time I have reload the page.