Do you know a post office in warsaw near center, from where i can send some letter to a foreign country?
There are plenty. They all have 'Poczta' written over the door. The biggest one is at ul. Swietokrzyska 31-33 by the junction with ul. Jasna. Make sure you are in the larger of the two rooms (off Swietokrzyska, i.e. furthest from the corner of the building) and that you press the appropriate button on the machine (the button marked 'listy') and wait until your number flashes up on the indicator. Make sure you wait near the windows and be assertive about queue-jumpers.
How priority mail is called in polish?
Just pick up one of the blue stickers marked 'priorytet' and give it to the person behind the counter along with whatever you want to send.
And are envolve also available in those post office?
There are kiosks selling envelopes inside the main post office. make sure you have addressed it before you get to the counter.
Any polish language tips to visit those office
Any good phrasebook has a section on visiting the post office.
It is called priorytet. It is the same as air mail, only the name has been changed. Probably some Brussels eruocratcrat behind hsi desk thought it up. They are aslways coming up with dubious innovations
It's always been called that during the 12 years I've lived here and in any case doesn't always go by air for shorter distances, so air-mail would be a misnomer. Nothing to do with Brussels, hardly dubious and not an innovation either. Maybe you'd prefer if everything kept its PRL-era name.
To the OP: It might be easier and quicker for you to go to a smaller Post Office - the centre and suburbs are dotted with them. If you give some idea of where you are, we can tell you the nearest one.