Minting an NFT is its initial creation and is done most commonly on NFT Drops.
So you want to mint an NFT? What you need is a cryptocurrency wallet with some crypto in it. For this example we will be ethereum so Metamask wallet is the most popular one.
One you have some ethereum in the wallet you need to find an NFT drop that is either about to happen or is currently active. For this you can check NFTCalendar.wiki upcoming or active NFT list.
Once you have found a project that you wish to mint, navigate to the official twitter or discord channel and then follow the official links to the minting page.
This is important; you must always follow official links. Scammers are cloning websites using similar domain names so make sure you one the right website.
Click mint and it will connect your Metamask wallet to the website that's easy at no cost, then click mint and usually you can choose your desired quantity and then mint. Metamask will pop up showing you the free and an estimated gas fee if you are happy and all is in order click confirm and your mint will happen in a couple of minutes.
Leave the Metamask open until its transaction is confirmed. In most cases your NFT will be visible on platforms such as Opensea within a few minutes.