I have been offered a job but the boss said he can't provide an appointment letter and designation as per my application.

At the same time he mentioned that he wouldn't provide the designation as per application. That he can only give me a suitable designation after I serve the company for few months. I applied for Social Media Executive position. I am very confused because to whether I should accept this offer because it doesn't have appointment letter or any designation. He only mentioned verbally that his employees don't have any appointment letter but only offer letter. He has yet to come up with an appointment letter. Its is a company that provides foreign worker to all sectors and also consultation regarding any labor law. Please advice.

To me it appears very murky and without even an apptt.order, no use for the future. I would suggest, if you have better option try that. Before that have a due diligence done and above all if this is for a job offer from abroad, I have little knowledge about HR practices there. Exercise due caution pl.