MacBook displays usually work at a scaled resolution, which uses the extra pixels of higher resolution screens to improve the clarity of text on the screen while maintaining the same size. However, this basically leads to a "zoom in" on the screen with anything that is much bigger than it should be.
If the display works at its native, unscaled resolution, you'll have much more workspace, which can be great for anyone trying to extract every centimeter of their workspace from a smaller MacBook.
Try the built-in controls first
Apple includes some controls to change the magnification of the display, which you can find under the "Display" settings in System Preferences:
If you are currently using the default settings, it is probably best to try it before using a third-party solution.
Run in native mode with the Retina display menu
Retina display menu is a simple application in the menu bar that allows you to select a custom resolution from a drop-down list. It is an older application but has no problem with macOS Mojave. If it ends up breaking in the future, you can try SwitchResX, which has been updated much more recently, but is a paid application.
Download the DMG file for the application from the version link at the bottom of the application page and open it. From the menu bar icon, you can select the resolution to execute.
RDM allows you to run higher resolutions than your native display, but they will be fuzzy because they will have to interpolate. Here, my 13 "MacBook has a native resolution of 2560 × 1600, but is able to run closer to 4K with scaling. It will not look very good and may be too small to read, so it's best to stay with your native resolution. You can find your native resolution under the "View" tab in About this Mac.
RDM supports multiple displays at once, and even to change refresh rates for high refresh rate displays, but may be limited if you are using an older DisplayPort cable.
It's not without some bugs and inconveniences. Even if you launch the application at startup, it will not load your default resolution, allowing you to select it manually. In addition, if you use multiple monitors, each time you unplug your secondary monitor, the default settings for your MacBook monitor will be restored and you will need to reselect the resolution you are using again. Sometimes there will be a bug and you will have to select the resolution twice. But overall, he does his job pretty well.
Image credits: guteksk7/ Shutterstock