Open your project in QGIS
Make sure the map canvas shows the area you want to save
Go to Project
Select Import/Export
Click Export Map to Image
Choose the file name and save location
Select the image format
Set the image size and resolution if needed
Click Save
If you want a layout image, open the Print Layout
Add the map to the layout
Go to Layout
Select Export as Image
Choose the file name and save location
Click Save