Let say item A has a part number of 123A. 123A will be used as the item title. Let say item 123A has an alternate part number of 456B used by other manufacturers. What would be a good way to have a main part number an and alternate part number that is searchable, etc.
Please be very basic in your explanation as I am a new user.
You can mention the alternate number in the description of the item. Then you'll need a good search tool that looks for products containing the phrases the searcher types in the search bar. Here is a good solution https://amasty.com/search-pro.html
You can create additional part # attributes. Doing this will allow you to control what to use in the layer navigation and what can be used in search.