Kenny is spot on. You need to design a process to push leads over to SFDC. What that process looks like should be decided by you and Sales.
For instance, I like to sync ALL records, so the two systems mirror each other. In order to do that w/o sending all leads to Sales, I setup something like this in Marketo;
1. Sync Net New Leads (assigns to SFDC Queue: Pre-MQL)
2. Sync MQLs (if they reach the lead score threshold, push to Sales)...How this is done is up to you, it could be a simple Change Owner flow or a trigger that forces the SFDC Lead Assignment Rules to move the Lead.
3. Syncs for existing Leads or Contacts
4. Fast Track - so this would auto push a lead whenever a certain Form or action was taken. Your Request a Consultation Form is a good example of an automatic MQL. Sometimes this is done by scoring that at +100 pts to ensure MQL, or just as a separate flow.
Feel free to reach out if you need more help