If I try a 30-day free trial of Microsoft 365, can I use it on two different PCs?

Yes, you can use a 30-day free trial of Microsoft 365 on two different PCs. With a single Office 365 license, users can install Microsoft 365 Apps on up to five different computers. This means you can have Microsoft 365 installed on multiple devices, including two PCs, as long as you are within the limit of five installations per license.

References:

• About Microsoft 365 Apps in the enterprise
• Try or buy a Microsoft 365 for business subscription
• Give your customers free trials of Microsoft products
• Try a different subscription