There is no country on earth (maybe except North Korea) where you can be forced to work. Slavery was abolished a long time ago.
Can your boss send you a piece of paper with whatever text he wants? Yes.
Does that force you to turn up and work? No.
However, there are legal ramifications you should discuss with a legal professional if you are unsure: contracts don't need to be in written form in all countries. In some countries there is a legal notice period that is specified in laws that are used when the notice period is not specified in the contract. If in doubt, ask a local legal expert.
Some advice: your question raises a ton of red flags. You don't have a contract. You did not submit documents. You don't know the legal base of your employment.
Get to know the legal base of your employment. Don't work for shady types without paperwork. Don't just drop out if you don't like it. Get a contract. Keep to the contract.