Need Help in Encryption

I’m trying to create my own encryption can I get some tips like what factors should I keep in my mind etc.

Step 1 - Don’t create your own Crypto (chances are you will create something that can be broken)
Step 2 - Use something tried and tested.

Recommended to use

The language I’m using is C++ is it OK?

Read the basic info about it!

Sodium is cross-platforms and cross-languages. It runs on a variety of compilers and operating systems, including Windows (with MinGW or Visual Studio, x86 and x86_64), iOS and Android. Javascript and WebAssembly versions are also available and are fully supported. Bindings for all common programming languages are available and well-supported.