how can i create my own library in turbo c\c++ compiler (v.3)

You will have better luck asking a museum. People stopped using Turbo C++ 20 years ago. Only very outdated schools teaching students questionable programming still uses it.

In a modern system, you would either
1. Compile the library to some compiler specific unit, place it somewhere in the compilers search path, and put the header file somewhere in the include path. Then you would compile, telling the linker to use that library.
2. Compiler the library to a shared library, place it somewhere in the standard library path, place the header somewhere in the include path and tell the linker to use the library.

there was no shared library folder 30 years ago when TC was created and maintained...