A Master of Ceremonies (MC) is the person who makes all the announcements at your wedding reception. At most venues this will usually be your wedding coordinator, who is trained and will perform the role professionally.
It involves welcoming guests to the venue, introducing the bridal party and announcing the formalities (ie. speeches, cutting of the cake, welcoming you to the dance floor if you are performing a bridal dance, farewelling you at the end of the evening, etc.).
Sometimes couples may feel obligated to have a friend or family member do this because ‘they did it at my friend’s / sister’s wedding’. It may also be a role you are tempted to give to someone who is keen to help but you don’t really have anything else to ask them to do for you.
And of course if they enjoy themselves too much, the results can be awkward and embarrassing for everyone involved. That is not something you want your wedding to be remembered for.
So the consideration is do you know a friend who will be reliable and competent when speaking at your reception, or should you go with the safe option of a professional? It’s your choice.