Although Query Suggestions are not an out-of-the-box feature for our Salesforce B2C integration, you can customize the Autocomplete menu, as needed (including the implementation of Query Suggestions), in the appropriate config file based on your integration type (as listed in this documentation).
Though not directly related to the Salesforce integration, you will find our general guide to implementing Query Suggestions for Autocomplete here.
Please note that guidance regarding front-end customizations is out-of-scope for our Support team.