Use Catfish to find files and file content quickly – note content search only works for text type files. Use Recoll for other file types.
Install using Synaptic Package Manager or from Terminal as follows:
sudo apt install catfish
Run it by selecting it from from Utilities or use the Search function and enter Catfish to locate.
Once running you should see screen below.
To search for content first click the settings cog and check “Search File Contents”.