How to add Billable expenses

When I go to the Billable expenses tab I get the screen Billable expenses with the word EMPTY, no button to create a new one. How to add Billable expenses.

Read the Guide.

Then, if you have questions, ask on the forum.

where can I find te tab new Billable expense

The link I included in my previous answer describes the process. There is no New Billable Expense button. Instead, when you spend money, you just select the Billable expenses account and the appropriate customer’s subaccount.