Which trigger to choose for an autoaction

Yes, after payement completed could be great for Stripe but it won't work for bank wiring.
But when talking with you I see a way :  just cuting it into two AutoActions. Should do the job !

What is the exact trigger "afterpayementcompleted" ? 

Best regards

Antoine

Banking wire would work fine too. The email would just be delayed until the wire came through. The way those payments work is the basket goes into a Pending state and you'd be emailing on a Completed state. Below is how to do this.

Global
Triggers: onCPayAfterPaymentStatusChange
User: Automatic
Access: Everybody
Conditions
Field: Custom > Value
Custom Value: [var4]
Operator: Equal To
Value: Completed

This just fires whatever auto action you have based off a basket being set into a Completed state. If you want to limit this to a specific payment gateway you can add the following condition to it.

Field: Custom > Value
Custom Value: [var2_gateway_account]
Operator: Equal To
Value: YOUR_PAYPAL_GATEWAY_ID_HERE

Hello
Your advice worked fine, thank you !

I have another question : I am using onCPayAfterUserRegistration in an email Autoaction, and I try to read selected plans with a substitution [var1] in the email body, but I get nothing. (I also tried with the reload user option, or with var1 as a reference).
Do you have a documentation about item in var (like var1_XXX =..., var2_YYY=...) ? Or at least hox can I get selected plans in var1 with onCPayAfterUserRegistration ?

Best regards
Antoine

var1 of onCPayAfterUserRegistration is an array of plan ids. So you can't extract a specific id out of it. It has to be treated like an array. For conditions you should be able to do something like the following.

Field: Custom > Value
Custom Value: [var1]
Operator: Does Contain
Value: PLAN_ID_HERE

That should match if the PLAN_ID_HERE exists in the $chosenPlans array. To access the array you'd have to do so by its integer index. So for example [var1_0], [var1_1], etc.. doesn't make much sense to try and substitute those in though and probably best to use PHP to some degree so you can better loop through the list of plans.

I wasn't thinking of extracting a specific plan_id ; I tried to read all content of [var1] i.e. I would like to get all selected plans IDs, in the body of y email... but as far as I know, it is not possible to use some php to read the [var1] array inside the mail body of a email autoaction, is it ?
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Another solution would be to use some SQL Query custom field : I have a custom field [cb_my_selected_plans] which lists all selected fields to display it in the user profile. But it seems that at the onCPayAfterUserRegistration trigger moment, this field is empty and cannot be used inside the mail body of the email autoaction - is it ?

Best regards.
Antoine

Turn on "Format Functions" and "Format Code Function" under Parameters and give the following a try. That might work to at least output the selected ids.

Another solution would be to use some SQL Query custom field : I have a custom field [cb_my_selected_plans] which lists all selected fields to display it in the user profile. But it seems that at the onCPayAfterUserRegistration trigger moment, this field is empty and cannot be used inside the mail body of the email autoaction - is it ?

This trigger fires before any subscriptions are created so you won't be able to use any information from later triggers or subscription integrations.