Princess Zelda gladly officiated Link and Malon's wedding.
Personally I headcanon that the sage of light (I forgot how to spell his name I’m embarrassed) was the one who sealed Link and Malon in marriage. However of course Zelda gave a special announcement of the joining of these two before the ceremony as Link and she are bffs. They also held like 2 receptions. One at Hyrule Castle. Only personal guests invited by Link and Malon, The Knights, Zelda and The King, were there at the private reception.
Link and Malon’s second reception was held at an even more private location…Kokori Forest. The Kokiri wanted to throw their own party for Link.
They even made Malon her own honorary Kokiri clothes since she’s “married into the family”. Skull Kid gets invited too.
They then ride off on Epona into the Lost Woods, there they have a honeymoon in Termina.