Use an encryption technique. I suggest you look up cryptography.
secret writing= code
"But the secret of good writing is to strip every sentence to its cleanest components."
"But the secret of good writing is to strip every sentence to its cleanest components."
"But the secret of good writing is to strip every sentence to its cleanest components."
enigmatic writing/cryptic writing /coded writing
Code
secret
code
code
code
A code is a secret way of writing. A simple code, for example, would be to use the numbers 1-26 as they correspond to the letters of the alphabet, and then write words with the numbers instead of letters.
PINK from Victoria's secret