Making a very large form user friendly

We are currently in the design phase of an app that requires at some stage, users to complete a form.

The form can be broken up into 3 sections. We will let the user then use a step process to fill out all 3 sections

eg.

Step 1(Member Details)

Step 2.(Beneficiary details)

Step 3(Transaction details)

Each of these sections contain roughly about 15 inputs

Ranging from Name to contact details to Marital status etc.

Obviously it would not be very good practice to fit it all into 1 screen and have the user scroll down to complete everything. And using an accordion approach is also not ideal as it makes the form seem very fractured.

What would a good approach be when trying to build large forms on a mobile only platform and are there companies who have incorporated this well enough that I can perhaps take inspiration from.