This depends on your policy. Some will cover working, while others won’t.
If you want to be able to take on temporary work while travelling, your policy may cover you for this as standard. If not you may be able to add it on as an extra before you pay for your cover. To do this, get your quote, click through to your preferred insurer, and see if you’re given the option to add work cover there. If not, contact your insurer directly.
If you’re travelling specifically for work as part of a business trip, or in order to work for a foreign branch of your current company, you’ll need business travel insurance.