Nick here from Shopify.
If you have multiple products with the same design, your best bet is to set up the product with variants. Shopify has a guide going through everything you need to know about variants here. Something to note is you mentioned about male and female t-shirts. I would personally make a distinction like that a separate product and have the variants more for size, color, material, etc. You can also see the YouTube video tutorial about adding variants to your products below:
Printful also has a guide on product variants which might also be of some use to you. You can see it here.
Hope this helps!
All the best, Nick
Hello there. To add to this, is it possible to use a Shopify + Printful platform to create a merged variant to not size/color variants, but design variants?
Great question! This is definitley possible through product variants. You can add variants to a product that comes in more than one option, such as size or color but will still remain as one product and not two.
In the Variants section of the Add product page, click Add variant.
Enter a name for the option, such as
Size, in Option name. Customers will see this name.
In Option values, enter each option value followed by a comma, such as Black shirt - white logo and White shirt - black logo and so on. Customers will see these option values when they are choosing a variant. When you enter a comma, the option values appear as tags. You can see an example using colors below:
If your variants differ in more than one way, then click Add another option. You can have up to 3 options for each product.
As you add the product options, a list of variants appears with the heading Modify the variants to be created. Uncheck the boxes next to any combination of options that you don't sell. You can also add prices, SKUs, and barcodes for individual variants, or use the defaults based on the product details:
Something else to note is that you can show different product images for each variant with variant images.
If you have already created a product and want to add a variant, there is a YouTube tutorial from the Shopify team below which goes through the steps aswell as the help guide here.