Suggestions
Suggestions allow users to propose changes to strings without editing them directly. The actual string value is changed after a reviewer approves the suggestion.
How to enable suggestions
Go to Project settings
> Advanced
> Suggestions mode
.

Adding a suggestion
Once suggestions mode is enabled, users can edit a translation or add a suggestion.

Reviewing the suggestion
When a translator adds a suggestion, it is visible in the translations view, but not active (meaning if translations are exported, there is still the old translation).

Once a reviewer comes along, they can accept the suggestion.

This is the moment when it will replace the existing translation.

If there are multiple suggestions, you are declining the others by accepting one.
All previously accepted/declined suggestions are found under a "Show all" checkbox.

Protecting reviewed translations
Tolgee offers a mode where translators can only edit non-reviewed translations directly. You can enable this in advanced project settings:

So now, when a translator opens a reviewed translation, they can only suggest.

Granular protection
If you want more direct control over edit permissions and suggestions, you can do it through Granular permissions.
Here you can, for example, only allow the user to Suggest
, so they can't edit any translation directly.

Accepting the suggestions is tied to the "Change state" permission (which is what all reviewers have).