The below article is relating to the bulk upload - Custom Employee Fields which can be found by navigating to:

Administration -> Company -> Bulk Upload

Custom employee fields will allow you to capture information about an employee which is not
already captured within the system.
You should ensure that you have created your custom fields within the system before uploading
the information. To learn more about how to do so please refer to this article.
In this template, you are entering the values for each employee against these fields.
Whilst creating your custom fields, it is worth making a note of which field names relate to the
relevant number.

The Custom Employee Fields bulk upload is under the Other Data section here:

Once you've selected the Custom Employee Fields bulk upload you'll be redirected to this page:

The page includes the following:

Employee Field

In the CSV the first column is called employee ID, this setting relates to what you enter in that column, For example if you have used the employee's names in the CSV the employee name option will need to be selected. 

Include archived employees in search?

When using the name or Works ID method, sometimes you may have multiple instances of the same employee with one active and one archived - if you set this to NO we will not search archived employees when matching and will only search your active employees. If you had 2 active employees of the same name, for example, this setting would make no difference.

CSV file to upload

This is where you will load your CSV when it is ready to upload. Press browse and select the CSV file.

Download help file and instructions

This option will download our bulk upload help file. This includes instructions on how to use each bulk upload and lets you know which columns are mandatory and which are optional, it's important to look at the relevant help file before performing a bulk upload so you can get it right the first time.

Download CSV Model

The second option downloads an example template for you to use for the bulk upload with all the headers needed for the bulk upload to be successful.

Editing your CSV:

When you download your sample CSV file it will look like this:

Employee ID - This field relates to your chosen Employee field on the bulk upload page, if you have chosen employee name this will be the employee's first and last name exactly as they are on NaturalHR, if this is either the system or Works ID, this will be either of those IDs exactly as they are in NaturalHR too. This field is Mandatory and Case Sensitive.

Custom 1 to 40 - The rest of this CSV is made up of all of the available custom fields, simply enter the value you'd like to be stored in that field for each employee in your upload. This field can contain numbers and letters and is Mandatory.

Important Note 

If you are using a Yes/No custom field if you are bulk uploading data for that field you need to insure you use a capital Y and N for Yes and No in order to pull the data through correctly