Can the payer complete the amount of the transaction himself?

Yes, there is a possibility to do. This can be implemented in two ways:

1. On the website you can put a form with a field for giving the amount, which will then be re-processed by the php file responsible for creating the transaction, and the buyer will be moved to the page of the transaction panel.
   The archive files should be unpacked and then the code from the index.html file should be placed on the page.
   The folder "tpay" should be moved to the folder containing the file in which the html code was located.
   In the payment.php file in the "tpay" folder you need to complete your ID, security code and description.
   The other parameters are optional and can be sent by POST method with the amount. The php file will automatically detect their existence and send them together with the parameters to the transaction panel.
   
   Form available at address
   
   
2. On the website you can put a form with a field for providing the amount in which you need to fill in your merchant ID.The archive files should be unpacked and then the code from index2.html file should be placed on the page. This form requires exemption from the checksum in the Merchant Panel.
   
   Form available at address