Pablo,

I may not be understanding your use case correctly, but it seems like the most straightforward way would be a lookup field to the Accounts object from whatever object you’re working in.

You could also drop a skuid table on your model for the Account object into your popup, and use a row action for the user to ‘select’ the account.

Selecting the account is the easy part (As Matt has described above).  Capturing the array of services selected and passing them through to your email tool (along with the Account)  will be more challenging.  Zach has written a post about passing multiple items selected to a third party email service.  https://community.skuid.com/t/how-to-add-marketo-send-email-mass-action-to-a-skuid-tab…

I think your mass action could start by opening a popup that captures account, and then the popup has a “next button”  that passed the Account and  the array of selected service items as described in Zach’s link. 

Thanks Matt and Rob, I’m going to try to explain it better.

I have a Custom object “Requests” where I store the requests of my customers. My products are Internet services (ADSL, Fiber,…).

I have a table of Requests and a mass action to select products and compose a conga email to request price.

This is working.

What I want is being able to select to who I want to send the message (but not in conga).

So, I have a model ‘Requests’ with all the requests (Adsl 2/1 in germany, Fiber 10/10 in Netherlads,…) And a model ‘Providers’ (Accounts with the record type ‘provider’),

I want to select requests in the table of requests, click ‘Request price’, select a provider, and then launch conga.

What I don’t know how to do is the select a provider step.

You probably have a mass action button on the Requests Table that is kicking off your “select products and compose a conga email” process.   I think you need to have the mass action button open a popup where the account is selected, and then have a “Next” button on the popup perform your “send conga message with requests” action.  The array of selected items should still be available for you to use in your conga merge. 

but from the popup I can call to the get selected items on the table?

Yes,  look at Zach’s Marketo example linked above.  Activate that code from the popup button.  The selected rows should still be available.