Which sentence is correct?
1.The policeman wears a uniform.
2.The policeman wears uniform.
Hi,
Let's look at the noun 'uniform'. Is it countable? Can you count 'one uniform', 'two uniforms', so on? I think you can.
Thus, the second sentence should be:
The policeman wears a uniform.
It depends on the context, but I think that in most cases you'd use #1.
Your grammar is also a little awkward. The definite article suggests that you are talking about a specific policeman. The present tense suggests that you are describing his habits/routine. That all seems like something you would seldom want to talk about.
Best wishes, Clive