Can someone explain to me the difference between the two and why I'd use one over the other? I'm very new to Sharepoint am needing all the help I can get.
SharePoint Web Part
Web Part is a reusable component or a server side control that can be added inside a SharePoint page.
Web Part code runs directly on the SharePoint server.
There are several out-of-box Web Parts available in SharePoint and one can also build their own custom Web Parts.
You can use Server Side Object Model / CSOM via C# .
For more details check Creating Web Parts for SharePoint
- Add-ins can be developed on both SharePoint Online and in On-Premise offerings.
- Add-ins don't have custom code that runs on the SharePoint servers.
- Almost all major types of SharePoint components can be part of a SharePoint Add-in, including pages, lists, workflows, custom content types, list templates, Web Parts, and more.
There are two basic kinds of SharePoint Add-ins —
- SharePoint-hosted and
Add-in can be published to Microsoft’s public SharePoint store or hosted in a private store.
Provide you with the simplest marketing and sales system based on a Microsoft online add-in store.
Maximize your flexibility in developing future upgrades.
- Maximize your ability to take advantage of your existing non-SharePoint programming skills.
For more details check SharePoint Add-ins