First approach: langck
langck is a plugin Joomla simple implementation that makes it possible to condition the display of sentences or groups of words to the current language.
Simply insert the necessary tags of the form:
Note that this plugin can also be used to point to one or other of the modules or plugins according to the current language. Ex:
{tab A propos}
{article id="346"}{/article}
{/tabs}
{/langck}
{langck lang=en-GB}
{tab About}
{article id="347"}{/article}
{/tabs}
{/langck}
In this example we will rename the About tab to About and use article 346 for French, article 347 for English
Second approach: Web-T
WEB-T for Joomla - European Commission is a component Joomla which allows you to translate articles one by one by creating the associated article of the desired language.
Configuration
You must have previously created your account on the portal Web-T.
This is very well explained on the site Web-T, a multilingual automated website translation solution developed by the European Commission - The Joomla Community Magazine
Web-T, a multilingual...(extract)
Click on the link at the bottom of the interface “Set up an account for eTranslation”:
https://website-translation.language-tools.ec.europa.eu/automated-translation_en
From there click on the button Get your credentials here:
https://webgate.ec.europa.eu/etranslation/public/requestApiKey.html
Then you have to configure the credentials in the extension
Then the configuration of the extension; personally I put in the configuration 
Translate article on save
Translation
Once the extension is activated, simply declare a language for the article you want to translate.
When you save the original article, the associated article is translated automatically.