Custom fields are not visible in the mobile for Time sheet module
Successfactors - Employee Central
Custom fields are not supported in mobile for time sheet module
The Product Management has confirmed that this is an enhancement.
Currently the Enhancement has no fix date, and is currently in discussion for b1711 but not confirmed. You can track the release of this Enhancement by checking the release notes in each release for ECT-61493.
Time sheet mobile custom field , KBA , LOD-SF-EC-TMS , Time Sheet , Product Enhancement