Create the object called “Customer” and create the Master-Detail Relationship on Customer object so that Customer will be the related list to Account record. Create the field called “Account Manager” on Customer object which is lookup to the user object. Now Logic is when we create Customer record for account record, then the user in Account Manager field will be automatically added to Account Team of that associated account.

trigger InsertAccountTeam on Customer__c (after insert) {

List atm_list=new List();

AccountTeamMember atm = new AccountTeamMember();

List newShare = new List();

if(trigger.isInsert)

{

For(Customer__c c:Trigger.new)

{

if(c.Account_Manager__c!=null){

atm = new AccountTeamMember();

atm.account id=c.Account__c;

atm.teamMemberRole='Account Manager';

atm.UserId=c.Account_Manager__c;

AccountShare shares = new AccountShare();

shares.AccountId=c.Account__c;

shares.UserOrGroupId = c.Account_Manager__c;

shares.AccountAccessLevel='Read/Write';

shares.OpportunityAccessLevel = 'Read Only';

shares.CaseAccessLevel='Read Only';

newShare.add(shares);

atm_list.add(atm);

}

}

if(atm_list!=null)

insert atm_list;

if(newShare!=null && newShare.size()>0)

List sr=Database.insert(newShare,false);

}

}