I want to make "projects" field mandatory while importing data into quickbooks for Bills.

Fiat is right that we can't make the project fields mandatory when importing, @ahmed-rais20-gma.

I'd like to elaborate their suggestion on how to create your project manually instead

If you haven't already set the Projects feature on your account, follow these:

1. Click on the Gear ⚙ icon, then choose Account and settings.
2. Access the Advanced tab.
3. Locate the Projects section and click on Edit ✎ to open it.
4. Turn on Organise all job-related activity in one place.
5. Click on Save and then select Done.

Then, you can create a new project:

1. Open the Business overview menu, then click on Projects.
2. Choose Start a project if this is the first time you are creating. If not, choose New Project.
3. From the Project Name field, type in the project name.
4. Choose the project customer from the Customer ▼ dropdown.
5. Enter any notes or information about the project in Notes.
6. Click on Save.

As your company takes on more work, your project list will grow. You can add new and existing transactions to a project once it has been created. To do that, follow steps 3 to 8 from this module: Set up and create projects in QuickBooks Online.

I'm also adding this helpful guide about adding unpaid and paid invoices to projects in QBO.

Feel free to reply to this conversation if you need extra help with handling projects/bills. I'm always around to back you and your business. Please take care!