Removing index.php from the URI in Codeigniter 3 - apache

Question

I have done all the said solutions to remove 'index.php' from the URI. The procedure I took is as below:
In .htaccess:
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L]
In config.php
the base_url is set to
$config['base_url'] = 'https://trawellmate.com/';
Removed index.php from
$config['index_page'] = '';
These are the suggested solutions. But nothing worked. I am using SSL and all non requests are redirected to https://trawellmate.com. Following is the lines added to achieve in .htaccess:
#FORCE NON-WWW REDIRECT
RewriteCond %{HTTPS} off
RewriteCond %{HTTP_HOST} ^(?:www\.)?(.*)$ [NC]
RewriteRule (.*) https://%1%{REQUEST_URI} [L,R=301]
Earlier with non SSL(in development mode in localhost) it was working fine. Since, we are about to go live, a quick help will be deeply appreciated.

Answer 1

You may try to use the following rules. It worked for me.
RewriteEngine On
RewriteCond %{HTTPS} off [OR]
RewriteCond %{HTTP_HOST} !^www\. [OR]
RewriteCond %{HTTP_HOST} ^yourwebsite\.com$ [NC]
RewriteRule ^ https://www.yourwebsite.com%{REQUEST_URI} [R=301,L,NE]
RewriteCond %{THE_REQUEST} ^[A-Z]+\ /index\.php(/[^\ ]*)?\ HTTP/
RewriteRule ^index\.php(/(.*))?$ yourwebsite.com/$2 [R=301,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?/$1 [L]

Answer 2

Allow overriding htaccess in Apache Configuration (Command)
sudo nano /etc/apache2/apache2.conf
and edit the file & change to
AllowOverride All

Answer 3

Below .htaccess configuration works for me
RewriteEngine on
RewriteBase /<app_directory>
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /<app_directory>/index.php/$1 [L]
I've placed the .htacess file in /var/www/html ie. Parallel to application directory
Hope you have enabled mod_rewrite module for apache, Also add below block in virtualhost file(000-default.conf) of apache. Please restart server after changes.
<Directory /var/www/>
Options Indexes FollowSymLinks
AllowOverride All
Require all granted
</Directory>