May you please tell me the website where I can register for domestic or foreign embassy jobs ?

If you want to go to a shiity Embassy in some dump country just apply online at the state department. If you want to go to some cool place like Thailland, better have a Senator as your lover.

Apply for jobs - if you have all the requisite education & other qualifications - through your State Dept or Ministry of Foreign Affairs, etc, in your country of citizenship. Citizenship is a usual requirement for any diplomatic sort of job. And typically, you will work in your country of citizenship before you might qualify for assignment to one of your country's foreign missions, consulates, or embassies.

Without knowing our country of citizenship its very difficult to answer your question but even 3rd World Countries diplomats are well educated and have a degree in something pertinent to the work. Check out the Foreign Affairs mission of your country and see if they are hiring. Many countries offer diplomatic postings as a reward to successful business or helping the government in someway. Not the case in the US, except for top ambassadorial positions within several countries but we are the exception, not the rule. Fluency in a foreign language is also normally required so.... keep researching.