This is a mention from a SEO scan. Is there an easy way to implement this?
<link rel="alternate" href="http://example.com/" hreflang="en" />
When to use Hreflang attribute:
Hreflang attribute is used in multilingual and multi-regional environments. It’s multi-lingual declaration for the site.
Hreflang attribute is used to resolve the following issues:
Duplication content because of targeting different markets with the same language.
Duplication content because of targeting different markets with different languages.
Targeting issues owing to targeting a country market with different languages.
Wrong specific data (e.g. prices, currency or date formats).
I have found one module to solve your issue.
Please check this module