There are few tools which can be helpful in this case:
- https://github.com/SitecoreUnicorn/Unicorn
- https://doc.sitecore.com/xp/en/developers/101/developer-tools/serialization-plugin.html
- https://www.teamdevelopmentforsitecore.com/
In general the idea is to serialize a set of items which you are working on (not entire database) to disk as text files. This will allow you to version them using git, make them a part of the deployment package and install them on the staging server.
The method itself is different depending on which tool would you like to use.
Additionally you can move items between different environment using packages. You can create a package with items from the Desktop view
You have to select the items or entire item branches and include them in the package. Once all your items are included, you can download the package and install it on any other instance.
Please note that unlike the tools used to serialize the items it is hard to version the items when they are exported as a package or automate the whole process. On the other hand you can create such a package quite fast and it is available out of the box in any version of Sitecore.