I would like to make a FM transmitter but would like that only mine FM receiver can take my transmitter. To perform this, I imagine I also need to make some alterations in FM receiver (that is usually accessible in market).
Please direct me what are the major things I need to modify or do in FM receiver and transmitter.
The only way is to encode your signal such that others cannot decode it. There are many ways to do this.
Since you are actually TRANSMITTING it into the free air, there is no way you can ensure that no one else picks it up.
What sort of signal/ information are you planning on transmitting using your FM transmitter ?