If you want to embed single program which is runnable from your website then you "share" button to get embded link. Details are provided at
https://www.onlinegdb.com/blog/introducing-runnable-cc-code-snippets/
If you want to embed OnlineGDB compiler to your website so that your website users can compile and run from website, then contact us
https://www.onlinegdb.com/contact with your website details