Foreign nationals who want to live in the UAE long-term must have a Residence Visa. In addition, if you want to be allowed to work, you must also have a work permit for the UAE.
However, before everything, you need an employer willing to hire you and start the necessary procedure to procure your employment visa and work permit for the UAE.
The employment visa for Dubai, or any other emirate in the UAE, comes with specific rules ensuring the rights of workers are not violated.
Any foreigner who is over the age of 18 can work in the UAE, provided that they meet the standards set by the Ministry of Human Resources and Emiratisation (MoHRE). There is no maximum age for who can be employed in the UAE, but for workers over the age of 65, the company pays a higher fee.