Letter of Recommendation from Capgemini

I have been working in Capgemini since December 2021... and I will be pursuing Master's in USA, planning for Fall 2024. I need 3 LOR's from which 2 LOR's I am getting from my College and 1 from Capgemini. The issue is when I asked my Manager for the LOR, he declined as it is not allowed for them to write LOR directly. I contacted my HR regarding this, he gave me a portal HR Service Letter. I am not sure about this process. Can anyone guide me how to get LOR from Capgemini? Thank you! #applicationprocess #LOR #capgemini