You can upgrade from a free plan to any of the paid plans in Zoho Projects based on your business needs.

1. Click your profile picture in the upper-right corner of the Zoho Projects top band.
   
2. Select Subscription Details to view the pricing details.
   
   
3. Choose a plan according to your business need and click Upgrade.
   
4. Select your Yearly or Monthly subscription using the toggle.
   
5. Enter the number of users.
   
6. Enter the add-ons if needed.
   Client User: External users from organizations that are typically customers
   Support: If paid premium support is required (Min of 25 user licenses will need to be purchased to subscribe for Premium support)
   Read-Only Users: users with only view permission in the portal
   Resources: Typically machine type resources add on.
   
7. Click Proceed.
   
   
8. Enter the billing details and payment details.
   
9. Click Proceed.
   
10. Click Confirm after verifying your order summary
    
11. A confirmation message about the upgrade is displayed.
    

This upgrades your plan to a paid plan and the required amount is automatically transacted from your credit card. In addition, you will receive a purchase mail along with the plan details for your records. Payments are recurring and your credit card will be charged automatically.