Hello,
When you said memory, you meant RAM, right?
A USB flash drive cannot add actual RAM to your laptop. On some Windows computers, however, you can use ReadyBoost, which uses the drive as a cache to slightly improve performance.
Insert a fast USB flash drive. Open File Explorer and select This PC. Right-click the USB drive and choose Properties. Open the ReadyBoost tab.
Select either:
Dedicate this device to ReadyBoost, or
Use this device, then choose how much space to reserve.
The USB drive should have at least 500 MB of free space, although using several gigabytes is more practical.
Also, fyi, if your laptop has an SSD, Windows may not show the ReadyBoost tab because the SSD is already much faster than USB caching.