I have never heard the term 'will had' used in standard English, however 'will have had' is a standard construct, used to describe something that will have happened by some future time. The precise timing of the future event is typically subject to some uncertainty.
"John will have had time to run his errands by the time we get there."
"Mary will have had the opportunity to review your resume carefully before your interview next Tuesday."
"They're very busy, but the mechanics should have had a chance to look at your car by the time you get back from your trip."
Note that the 'had' in each phrase isn't necessary at all, in fact it makes a bit of a constructive mess. You will likely encounter it only in spoken English.
So, why? Let's look at the last example.
In their mind, the speaker first translates 'have a chance' as a block of future time to be allocated to the subject project. So when they say "I will have a chance to look at your car...", they're thinking, say, 'two hours'. This verbal construct 'have a chance'(which they mentally use to represent 'two hours') then gets preserved as they start thinking of the owner returning and mentally switch to thinking of that block of time in the past tense "I had a chance to look at your car..." ('had a chance' = 'found two hours' - success!)
and so by the time their mental thought processes end up expressing an opinion, in the past tense, on the probability of a future event, with a finished car repair and a happy owner, it becomes
"I will have had a chance to look at your car..."
which makes more sense if you realize the speaker is thinking:
"I will have found two hours to look at your car..."
and that's how we end up with a common use, particularly in spoken English, for the future pluperfect:
"I will have [had some time, exactly when unspecified] to do [something]".