How can i make a plugin that when I tap a sign it gives me item when the sign has 1st line => Command 2nd line => Item
From a public plugin developer's perspective, it's not advisable to make the plugin's action rely on sign text. It has many disadvantages, such as 1) incompatibility with other plugins (multiple plugins using the same sign text), 2) insufficient typing space (limited to 15 characters per line), 3) uncustomizable text appearance and 4) uncontrolled input source. For example, a sign may be created before the plugin is installed, or from a downloaded map, hence uncontrolled permissions.
I wanted to make a shop which sells custom named weapons with enchants How can i sell these without using signs or commands is there another way
A good alternative offering a similar functionality is that you register block positions as shops, regardless the type of the block.
Could you please generously show your ability to create your own things? We're just talking at the theory level, and you're asking is to do everything from writing the code to thinking what the plugin should do for you.