What is mean by amlifying an RF signal

What is mean by amlifying an RF signal ? I mean what is happening when amplifying an RF signal ? Is it increase signal voltage or current when amplifying it ? Please help me

yes, it increase the signal voltage and current.
Normally the RF impedance is 50 ohms, and the RF Power=V^2/R and Power=I^2*R.

Can you explain about RF impedance ? I already know the resistors , capacitors and inductors have impedance and how an RF signal have impedance ? Please teach me

Regards
Aneesh T V

Well, you can read microwave technology textbooks.
That is microwave transmission lines, to keep TEM mode in microstrip line, just an example, specified RF characteristic impedance. It maybe a long story.

Find a textbook on microwave circuit theory and start reading up on transmission lines.
For starters, check out this article: Characteristic Impedance - Microwave Encyclopedia - Microwaves101.com