Hello Rakesh!

Since you have not clearly specified the molecule containing OH and Cl groups, I assume one example and assume you are asking about the scenario of OH and Cl group attached to benzene ring. Now, OH and Cl both are electron donating groups and contain lone pair of electrons which come in conjugation with pi electrons of benzene ring and hence participate in delocalization of pi electrons of Benzene ring, which is the process of Resonance. Since, both are electron donating groups, they have similar resonance structures, exhibiting +R effect and similar resonance. However, Cl being strongly electronegative, also exhibits strong -I effect which also withdraws electron density away from the ring.