There are 2 options on how you can offer extra services using the One Step Checkout extension. Let’s consider them closely.
One of the most common additional services is gift packages. To enable the fee for gift wrapping, go to Stores > Configuration Amasty Extensions > One Step Checkout and open the Gift Wrap section. Then, configure the following options:
To create a new checkout field, go to System > Manage Checkout Fields. Choose the block where you want to add the field and click the Add Order Attribute button:
In the opened window, fill in the general information about the new field:
Then scroll to the Attribute Type Settings. They may vary depending on the input type you chose before.
Next, customize the Attribute Display Settings:
And define whether you want or not to:
In the Title, Tooltip, Options tab, you can add titles of this field in other languages and set up options for multi-option input types.
In the Shipping Methods tab, you can set for what shipping method this field should be displayed.
Note: using this option, you’ll need to process these requests manually, as they are not added to the order total automatically.
See more details on One Step Checkout for Magento 2 page
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