We are but a small (10-15) team in a very large company - so the first day starts with reading the general company docs, supplemented with an funny personalized introduction to our team and what we do. Otherwise you are overwhelmed by getting to know your laptop, team and introduction banter.
Each day of the introduction week we try to have a lunch with one collegue or the entire team (now with working remotely, it is trying to be in the office for the occasion), and also at the end of each working day a personal conversation with another colleague of the team.
During the two weeks of onboarding the new member will be introduced to the devops, the tools we use, the projects we do, etc etc etc. There is also plenty time to get to know the techniques we work with using Pluralsight courses (because we have a old .NET Framework stack and a new .NET 6 stack).
Besides that, there is also a series of practices to do. Via a prepared project, the employee will, together with the courses mentioned, build a small application. Each assignment is discussed and code reviewed.
At the end of the two weeks the new member knows the entire team and is ready to collaborate in a client project.