You can define by yourself which images and text you want to turn into templates so they can be a) edited/changed by the customer within the personalize form, and b) addressed by you externally through API functionality (basically you can change template content of your products through your own website).
“make this a template object”
This turns the selected text or image into a template object. When you do this, you have several fields/options:
Product page label field: edit here the text that will be displayed as the field label in the personalize form. You can enter pretty long texts, so you can give customers a brief description or hints, e.g. “CAPTION - Enter your photo caption”.
URL parameter name: This one is VERY important. Enter here a unique reference code for your template field. This is the code with lets you address your template fields through external API links, AND can also be used to sort the template fields within the personalize form, which is done alphabetically. So, if you have as an example a name, address, a city, and a message field that can be edited, you may want to give the name field the URL code text01, then text02 to the address field, text03 to the city field and finally text04 to the message field, so they appear in this specific order.
Allow editing on product page: This specifies if the template field can be edited within the personalize form or not. Usually you have this one enabled, but in some cases you want to disable it, e.g. when you have some images or text that you want to be able to address & set via API links but wannot that the customer can change them in the form.
IMPORTANT FOR IMAGES - Inner fit/fill mode: When you use template images, this option is extremely important to set correctly, depending on your needs / how the user’s image has to replace your placeholder. When using template images, first choose an adequate placeholder image at the correct size and make it a template. Then select the FILL mode, if you want the user’s image to fill completely the area of your placeholder - in this case, the exceeding parts of the user’s image will be cropped. For user images that have to fit within your placeholder area in its whole without anything being cut, e.g. logos, select the FIT modus. The NONE modus is pretty obsolete IMO, this one displays the user’s image at its “original” size and ratio which can be pretty random. Never used it.
“Make objects permanent and always visible” is not a template option, this applies to any object and defines if the object can be deleted or not.
Hope this helped.