How can I hide/encrypt my files from another user using the same server

As others have pointed out, you can't stop system administrators (anyone with sudo access) accessing your files. Even if you encrypt them, if you need to access their content on the server, then an admin can snoop on you while you do. This is true in most/all operating systems.

Your home directory is readable by all other users, usually by default. In comments you said your home directory had read permissions by all users.

Often all you need to do to stop other regular users is change the permissions on your home directory;

chmod 700 ~ 

This will block all users except for root (admin) from your home directory.

If you need to encrypt your data for legal or commercial reasons then this is often not enough unless you have been informed that the drives are encrypted.

reading the title "hide/encrypt my files " ...

To encrypt a file (in the example below, denoted F);

(e.g with openssl,

using AES with CBC as Mode Of Operation)

AES - Advanced Encryption Standard

CBC - Cipher Block Chaining

openssl aes-256-cbc -base64 -pbkdf2 -in F 

Note: pbkdf2 and -iter is not supported by lower versions than OpenSSL 1.1.1

One could use -iter <integer> to add a extra layer of security.

This, makes it harder(by making it slower) to try to brute force(guess) the password, but if a ridiculous amount of iterations is used, it will take very long - although, this is symmetric encryption and that is quite fast most of the time, just thought of mentioning this.

Note: use >= 10000 iterations

openssl aes-256-cbc -base64 -pbkdf2 -iter 10000 -in F 

Decrypt

Denoting encrypted file "file.enc":

cat file.enc | openssl aes-256-cbc -base64 -pbkdf2 -d 

Encrypt multiple files

(With the same extension) instead of encrypting every file:

For example,

to encrypt all files ending with .odt, in the folder odtFiles with a unique password (which is asked for interactively) and output the encrypted files to <originalfilename>.enc:

find odtFiles/ -name "*.odt" -type f -exec openssl aes-256-cbc -base64 -pbkdf2 -in {} -out {}.enc \; 

References:

Related OpenSSL 1.1.1b warning: Using -iter or -pbkdf2..

OpenSSL Manual