for OpenCart 2.3.X
Adding following:
RewriteRule ^cart/?$ index.php?route=checkout/cart [L]
RewriteRule ^checkout/?$ index.php?route=checkout/checkout [L]
RewriteRule ^contact/?$ index.php?route=information/contact [L]
ReWriteRule ^account/?$ index.php?route=account/account [L]
ReWriteRule ^account/edit/?$ index.php?route=account/edit [L]
ReWriteRule ^account/password/?$ index.php?route=account/password [L]
ReWriteRule ^account/address/?$ index.php?route=account/address [L]
ReWriteRule ^account/wishlist/?$ index.php?route=account/wishlist [L]
ReWriteRule ^account/order/?$ index.php?route=account/order [L]
ReWriteRule ^account/download/?$ index.php?route=account/download [L]
ReWriteRule ^account/reward/?$ index.php?route=account/reward [L]
ReWriteRule ^account/return/?$ index.php?route=account/return [L]
ReWriteRule ^account/transaction/?$ index.php?route=account/transaction [L]
ReWriteRule ^account/recurring/?$ index.php?route=account/recurring [L]
ReWriteRule ^account/newsletter/?$ index.php?route=account/newsletter [L]
ReWriteRule ^account/login/?$ index.php?route=account/login [L]
ReWriteRule ^account/logout/?$ index.php?route=account/logout [L]
ReWriteRule ^brands/?$ index.php?route=product/manufacturer [L]
ReWriteRule ^special/?$ index.php?route=product/special [L]
ReWriteRule ^account/vouchers/?$ index.php?route=account/voucher [L]