If your new to UAE then Just submit ur Passport & visit visa and with in 3u20137 working days you will receive your MOL contract duly signed by your employer and then you too need to agree and sign with thumb impression if visa is unskilled visa for skilled workers sign is enough.If you are already working for a company in UAE then just submit your visa cancellation paper and passport copies to the new employer.Once you do this Your Employer will submit this to the Immigration department and You need to wait maximum of 7u201315 days for your E- work visa to generate.(Normally it took just 7 working days for mine .where in both the companies that I worked )Once this visa is generated talk to your employer whether if you want to exit the country or do an internal transfer . Ie Change of visa with out exiting.Soon after you enter or do the internal transfer your HR or PRO team will ask you to do the medicals with in 7u201330 days and then you will receive your medical fit to work certificate from health authority with 7u201310 days.Mean while you need to do the formalities for Emirates ID i.e Finger print and Eye scanning.Soon after they receive the medical certificate they will send it to the Immigration department for Visa stamping. Visa stamping will take at least 10u201320 days.Then your visa is stamped wait for the message from Emirates ID office.You will receive an SMS saying in which post office you need to collect the Emirates ID.Hope this helps you.