Uploading a file

I have a form

				  <form method="POST" action="buildings/add_building_engine.php">
				    <div class="form-row">
					  <div class="form-group col">			 
					    <label for="BName">Name (required)</label>
					    <input type="text" class="form-control" id="BName" name="Name" required>
					  </div>
					  <div class="form-group col">			 
						<label for="Number">Number (required)</label>
						  <div class="input-group">
							  <div class="input-group-prepend">
								<span class="input-group-text">#</span>
							  </div> 
							<input type="number" class="form-control" id="Number" name="Number" required>					
						 </div>
					  </div>
				    </div>
					<div class="form-row">	
						<div class="form-group col">			 
						  <label for="Floorplan" style="display:block">Floorplan (png format)</label>
							<div class="custom-file">
							  <input type="file" class="custom-file-input" id="customFile" accept="image/png" name="Floorplan">
							  <label class="custom-file-label" for="customFile">Choose file</label>
							</div>
						</div>				  
					</div>	
					<div class="form-row">	
						<div class="form-group col">			 
						  <label for="Notes">Notes</label>						  
						  <textarea class="form-control" id="Notes" name="Notes" rows="3"></textarea>
						</div>				
					</div>	
				    <div class="form-row">
					  <div class="form-group col">					  
					    <button class="btn btn-outline-dark btn-block btn-lg" type="submit"><span class="icon-ok"></span>&nbsp;&nbsp;Submit</button>
				      </div>
				    </div>
				  </form>

when it s submitted, I get

Array
(
    [Name] => luke
    [Number] => 66
    [Floorplan] => ac_icon.png
    [Notes] => 
)
Array
(
)

on

echo '<pre>';print_r($_POST);echo '</pre>';
echo '<pre>';print_r($_FILES);echo '</pre>';`

why is the files empty

Your missing enctype=“multipart/form-data”

the form attribute was missing…
enctype=“multipart/form-data”