In practice this is done through the jurisdictional police station or Karnataka's online Seva Sindhu services, usually soon after a tenant moves in. The duty sits with the landlord, not the tenant, though you will usually be asked to fill in an identity form and hand over ID copies. Keep your own copy of whatever form you sign, and ask your landlord if it has been filed.
The number
Landlord-side reporting is mandatory in practice; non-compliance has led to a landlord's conviction (Deccan Herald); verification is also available online via Karnataka State Police's Seva Sindhu services.
Sources
Where it comes from. Level 1 is a government or court page, level 2 established press, level 3 a portal's explainer, which gives only what is commonly quoted.
- Deccan Herald, https://deccanherald.com/national/landlord-convicted-failing-do-693271.html, level 2
- Karnataka State Police, https://ksp.karnataka.gov.in/page/FAQ/Online+Police+Services/en, level 1