???

Are you talking about the sink stopper, the part that goes up/down to stop water from running down the drain?

Here is a diagram and instructions:

https://www.bigbplumbing.com/clear-bathroom-sink/

Here is a video. The video quality is lousy, but he seems to explain it well.

https://www.youtube.com/watch?v=gXNes-InqPU

I have done this repair many times and hated it so much that when I remodeled my bathroom I changed all my sink stoppers to this product. No stupid little lever to rust. Easy to clean/unclog.

https://www.calfaucets.com/innovations/zerodrain

No, the tube that water leaks into, in that tube there is bootle cap, we cant take it out.

You aren't using the correct terms, so no one understands what you are asking.

Do you mean the drain? And someone put a real metal bottle cap down the drain?

Maybe you can post a photo of where the bottle cap is stuck, so we might understand your question.

In the circled area there is a cap. How i can get it out?

I can't take it apart, i dont have the equipment

"I can't take it apart, i dont have the equipment"

Unfortunately then you will not get the cap out.

I'd buy a coupler (whatever its called that attaches 2 sections of the white corregated drainage pipe you are using). Then I'd cut below where I thought the bottle cap was. Get the cap out. Then reattach the 2 open ends of your drain 'pipe' with the coupler (thingee.) (Actually I'm lazy, so if it was a sink I don't use much I'd just cut the drain pipe and use water proof duct tape to reattach it back together - and put a small bucket under it (and then call a plumber once I had another task for him to do.)

Buy new plumbing parts. Not that hackycrappy thing that’s there now. Every homeowner needs to own basic tools and to understand and be able to do basic plumbing like this.

Or call a plumber for a $120 fee.