If you claim universal credit and rent privately, the housing element is paid as part of your monthly universal credit payment. Unlike the old housing benefit system, it's paid directly to you rather than to your landlord. This means you're responsible for paying the rent yourself from the money you receive.
The housing element is calculated based on the local housing allowance rate for your area, not your actual rent. If your rent is higher than the LHA rate, you'll need to make up the difference.
There's typically a five-week wait before your first universal credit payment, which can leave new claimants without help for rent during that period. You can apply for an advance payment to bridge this gap, but the advance is repaid from future payments.
Importantly, under the reformed Ground 8 for rent arrears (post-Renters' Rights Act), the court must disregard any arrears that have built up solely because you're waiting for universal credit payments you're entitled to.