OnClickUpAsButton used externaly

How do I tell my player that my UI image has been clicked?

This is a question that can be solved two ways:

a) Broadcasting

Here is my attempt:

My "buttons" script I sadly deleted in rage so basically it needs to broadcast to ShieldReciever to function!

My players inventory script:

  void FixedUpdate()
     {
         if (Input.GetKeyDown("i"))
         {
             IsCrafting = true;
         }
         if (IsCrafting == true)
         {
             a.SetActive(false);
             b.SetActive(false);
             c.SetActive(false);
             d.SetActive(false);
 
         }
         if (IsCrafting == false)
         {
             a.SetActive(true);
             b.SetActive(true);
             c.SetActive(true);
             d.SetActive(true);
             Shield.SetActive(false);
             ShieldInput.SetActive(false);
         }
         if (Input.GetKeyDown("i"))
         {            
                 IsCrafting = true;            
         }
         if (IsCrafting == true)
         {
             Crafter();
         }
     }
     void Crafter()
     {
         if (WoodAmount > 2)
         {
             if (GoblinScalesAmount > 0)
             {
                 if (ShieldBought == false)
                 {
                     Shield.SetActive(true);
                     ShieldInput.SetActive(true);
                     if (ShieldIsPushed == true)
                     {
                         WoodAmount = WoodAmount - 2;
                         GoblinScalesAmount = GoblinScalesAmount - 1;
                         ShieldBought = true;                        
                     }
                 }
             }
         }
     }
     void ShieldReciever()
     {
         ShieldIsPushed = true;
     }

b) A function I do know about

If there are any please tell me!

Thanks!