Hi @Shild,
You can save reusable settings in InDesign, but there's an important difference between a document preset and an InDesign template.
If you want something available when you select File > New > Document:
Go to File > Document Presets > Define.
Click New.
Give your preset a name and configure the page size, margins, columns, bleed, etc.
Click OK twice to save it.
Go to File > New > Document and select your saved preset.
Ref: https://adobe.ly/4zk4t4s
If you want to save a complete design containing text, images, styles, and parent pages:
Open your designed document.
Select File > Save As.
Choose InDesign Template (.indt).
Save the template.
Opening this .indt file normally creates a new untitled document while keeping the original template unchanged.
One limitation to be aware of: InDesign currently doesn't provide a built-in way to add your own .indt files directly to the New Document template gallery. You can use File > Open Recent for quicker access.
Ref: https://adobe.ly/4z99lt2
I hope this helps.
Abhishek