Hi @majdouline 

Zapier works best for new data. Not historical data. Can you export registrants from GoToWebinar into a csv or excel file? If so, I would try using the Salesforce import wizard to create new leads. There are help articles on this https://www.dummies.com/business/customers/how-to-import-your-leads-into-salesforce/

As well as videos.
https://www.youtube.com/watch?v=FHBtZA-Jeps 



With the above in mind, if you wanted to push historical data through Zapier your best bet would still be to export the list (or retrieve it from an api if you can’t export) and then configure a zap that uses Google Sheets as your trigger step. 

and please if i have new registrant how can i do sync between gotowebinar and salesforce?

For new registrants, you would need to connect GoToWebinar and Salesforce. https://zapier.com/apps/salesforce/integrations/gotowebinar

I would suggest something like the following

Trigger: New Registrant in GoToWebinar

Action: Find or Create Record in Salesforce

if i have 10 new registrants i can do loop or something like that to insert all of them in salesforce?

Zapier will trigger EACH time there is a new registrant. If you have 10 new registrants Zapier will trigger 10 times

so how can i do that please? and can i schedule the trigger for example add all the new rigistrant for this week in salesorce?

I would start by visiting this page: https://zapier.com/apps/salesforce/integrations/gotowebinar 

and setting up the connection like the above screenshot. Then you can click on connect Salesforce and GoToWebinar. You will need to then configure the flow, test, and turn everything on. Once on the automation will happen as there are new registrants. 

please when i click to toggle the switch ON, what will be happen? is it paid or free?  and can i please choose my salesforce account and gotowebinar account once and for all to start the process automatically?

Yes, you can connect your salesforce and GoToWebinar Account. Salesforce is a premium app so you will need a paid zapier plan. 

i need to buy zapier plan that allow me to manage many account of GTW with salesforce  (for example i have 20 gtw accounts so i should create 20 zaps to insert the data in salesforce account?)