Is it safe to take generic medicine with same formulation as a branded one? i am talking about hypertension controlling drugs here

Usually yes: If it comes from reputable source. Hydrochlorothiazide is a drug that has been around for many years, so many manufacturers make them. Proof is control of bp, so try the generic and monitor your bp. If it is still controlled, you can stick with it.

Yes: Generic medications are considered to be identical (or almost identical) to brand, with the same drug, dose, strength, safety, efficacy, and indications of use.