NVivo generally recommends working with the project file stored locally on your computer because it is more stable and reduces the risk of file corruption. However, keeping a copy in OneDrive is useful for backup or sharing. Below are two safe ways to do this.

Method 1: Copy the project within NVivo

Open the project in NVivo
Click on the Share-button on the tab at the top of the NVivo window
Then hit Copy project
In the window that appears, select Windows (or Mac if you are using a Mac) and then click on Browse.
Navigate to your OneDrive and save the file.

Method 2: Copy the project via the File Explorer

This guide shows how it is accomplished in Windows 11, but the method is relatively similar for earlier Windows versions and macOS.

Close NVivo
Open File Explorer
Navigate to the folder where you have your NVivo-projects stored on your local drive (e.g. C:\NVivo). The project files are the ones that end with .nvp
Select all the projects you want to copy, then right click one of the files you've highlighted. Selct Copy (note that the option can sometimes also be on the bottom of the menu)
Navigate to your OneDrive and create a new folder if necessary.
Right click anywhere in the folder, and select Paste (note that here too the option could be at the bottom of the menu)
The files are now stored in your OneDrive.

Please note that you should still not work on the files that are stored on your OneDrive (or other cloud service) since it increases the risk that the project becomes corrupted. The projects can be copied back to your local drive as shown here, but in reverse.

NVivo's automatic Backup files

While you're working on the project, NVivo will automatically save a backup copy of it. These files end with .nvbak.

These files are created regularly (usually every 30 minutes) and can be used to restore your project after a crash. When you are creating the project, you can select where these files are stored. After the project has been created, you can change the location of the backup copy by navigating to File - Project Properties - Save and Recovery and click on Browse in "Recovery file location".

Note that these backup copies are not meant for primary storage, but instead as emergency recovery files in case something goes wrong with your project.