You can see "Read More ..." text in the links and buttons on almost all Joomla websites. Usually, it's on the home page, category pages, blog pages, and in some modules. It is defined in the language file and can be overridden by making a language override.
This procedure is similar to all Joomla versions. However, accessing the Language Overrides is different for different Joomla versions. So, we will explain it for all actual Joomla versions.
Joomla 3 Language Overrides
From the Joomla administrator panel go to Extensions > Language(s) > Overrides. Now, for the "Select Language & Client" select "Your Language - Site" (change "Your Language" with the language you are using in your Joomla site. Click New to create a new language override.
Joomla 4 Language Overrides
From the Joomla administrator panel click the System link. Under the Manage tab, click the Language Overrides link. Now, for the "Select Language & Client" select "Your Language - Site" (change "Your Language" with the language you are using in your Joomla site. Click New to create a new language override.
Make a Language Override
After accessing the Language Override page, the procedure to make an override is the same for all Joomla versions.
On the next screen, you will see the two panes. The right pane allows you to search for the string you want to change by entering its current value. So, in the Search Text field, enter "read more" and you will get several results.
The result you would need to change is most likely "JGLOBAL_READ_MORE". So, click on it and it will be automatically filled in the left pane. Now, enter your text for the Read More in the left pane, in the Text field. Finally, save your language override (click Save & Close). Your language override will be created.
Besides the global read more text, there are several more places where this text is used as you could see in the search results when you searched for "read more". Different strings are used when the title is included with the "Read More", for feeds, for modules, etc. So, you may need to repeat this procedure and make more language overrides.