How do I output a file’s URL in a Matrix field?
Assuming the field where your client can select the download is an asset field, you can use the following:

{% elseif block.type == "bladeBrochure" %}
    {% set download = block.download.first() %}
    {% if download %}
        &lt;a href="{{ download.url }}"&gt;Click me to download&lt;/a&gt;
    {% endif %}


Replacing block.download with the name of your field.