Find files containing multiple strings

Question

I use a command to recursively find files containing a certain string1:

find . -type f -exec grep -H string1 {} \\;

I need to

Answer 1

you can also try this;

find . -type f -exec grep -l 'string1' {} \; | xargs grep -l 'string2'

this shows file names that contain string1 and string2