Can I modify the .bashrc file instead of .profile file to customize my login?

Hello,
I got this question which tells me to customize my login script. Some people in the forums suggested to modify the .profile file in my home directory. I did so, but none of my customizations show up when I open the terminal after.

So, I tried to modify other files in my home directory, and found out that my customizations only works when written in the .bashrc file. When I open the terminal after modifying the .bashrc file, the terminal automatically displays my customizations (the directory that I have been sent to, the date and time, my customized prompt, etc).

This is great....only that I am not sure that I did the right thing. After all, everyone told me that I have to modify the .profile file. I'm getting headaches out of this. Any help? Thxs.

The .profile file is read only by the login shell. Any non-login shells will read the .bashrc file.
From the man page:

Login shells:
         On login (subject to the -noprofile option):
               if /etc/profile exists, source it.

               if ~/.bash_profile exists, source it,
                 else if ~/.bash_login exists, source it,
                   else if ~/.profile exists, source it.

         On exit:
               if ~/.bash_logout exists, source it.

       Non-login interactive shells:
         On startup (subject to the -norc and -rcfile options):
               if ~/.bashrc exists, source it.

In your case, the shell you're starting up isn't a login shell. So your .bashrc modification is correct.