After you file

thank you so much. i actually only set up the hsa today and did not have any contributions to it from my employer in 2023, i will however from this point on start to have my employer contribute to my new hsa from my payroll.  for the 2023 tax year hsa contribution, can i still ask my employer to contribute the full 8750.00 before the april 15th deadline into my hsa account as a lump sum? will that still count? thank you again.