If the Invoice icon is missing on your website footer please follow these steps to add it.
From your Shopify admin, go to Online Store > Themes.
Find the theme you want to edit, and then click Actions > Edit code.
In the Sections directory, click footer.liquid. If your theme doesn't include this file, then click theme.liquid in the Layout directory.
Find the following code in the file:
{% for type in shop.enabled_payment_types %}or
{%- for type in shop.enabled_payment_types -%}Replace the code which you just searched for with:
{% assign payment_types_from_config = shop.enabled_payment_types | join: ',' %}
{% assign enabled_payment_types = payment_types_from_config | append: ',esr_paymentslip_switzerland' | split: ',' %}
{%- for type in enabled_payment_types -%}