If your leave to remain is subject to a no recourse to public funds restriction, then you cannot claim Universal Credit because this could jeopardise your future applications.
Universal Credit cannot be considered for the purpose of E-LTRP.3.1 (Eligibility to Remain as a Partner)
E-LTRP.3.3. The requirements to meet this paragraph are-
(a) the applicant’s partner must be receiving one or more of the following –
(i) disability living allowance;
(ii) severe disablement allowance;
(iii) industrial injury disablement benefit;
(iv) attendance allowance;
(v) carer’s allowance;
(vi) personal independence payment;
(vii) Armed Forces Independence Payment or Guaranteed Income Payment under the Armed Forces Compensation Scheme;
(viii) Constant Attendance Allowance, Mobility Supplement or War Disablement Pension under the War Pensions Scheme; or
(ix) Police Injury Pension; and
(b) the applicant must provide evidence that their partner is able to maintain and accommodate themselves, the applicant and any dependants adequately in the UK without recourse to public funds.