cat
write to file with CAT
end with EOF to close
cat << EOF > ./user.txt
root
jimmy
joanna
EOF
note
The cat << EOF > ./user.txt
command will write to the user.txt file and EOF
will be the end of file instruction to close file.
Or
cat >> ./user.txt
Enter some
date here
to the file
note
The cat >> ./user.txt
command will write to the file and end the file with ctrl+d