I want to change opportunity.createdby to lead.ownerid,rectify my code

Question

I want to change opportunity.CreatedById to lead.ownerid,rectify my code

trigger on opportunity(after insert)
lst<ooportunity> opps=[select opportunityId,CreatedById from opportunity where opportunityId IN 
                               : Trigger.New];
list<lead> leads=[SELECT Id,ConvertedOpportunityId,OwnerId From lead where isConverted=true];
for(opportunity ops:opps)
{if(leads.Id==opps.OpportunityId)
{ opps.CreatedById=leads.OwnerId;
ops.add(opps);
}
update ops;

Answer 1

You can't, at least not like that.

Audit fields (createdbyid, createddate, lastmodifiedbyid, lastmodifieddate) are readonly and modified by SF internally.

There's a trick to open them up for example for data migrations (you're loading 7 years worth of opportunities, you want to record their real creation date so it doesn't show as a spike in reports). But you have only 1 shot at this. Only during insert.

https://help.salesforce.com/s/articleView?id=000334139&type=1 and https://help.salesforce.com/s/articleView?id=000331038&type=1

You'd need to tick something in setup, this causes 2 magic checkboxes to show up in profiles/permission sets. Then you'd edit your profile (or create new permission set and assign to yourself).

You'd need to change your trigger to before insert (but if it's before - the lead is still being converted, the opp id isn't known yet - so you can't match it by Lead.OpportunityId)... And even then - this feature is aimed at sysadmins, I doubt normal user without "Modify All Data" can do it.

Rethink your business scenario. Maybe you want to set Opportunity.OwnerId, not CreatedById?