You need to first create a your module and then create a static>src>fonts folder and then create a scss folder inside

static>src and inside of  scss folder a create a new scss file.

@font-face {
    font-family: PPNeueMontreal-Medium;
    src: url('../fonts/PPNeueMontreal-Medium.woff') format("woff"),
    url('../fonts/PPNeueMontreal-Medium.otf') format('truetype');
}

.page {
        font-family: PPNeueMontreal-Medium;
        text-transform: uppercase;
}

and then add this portion in manifest file. 

'assets': {
    'web.report_assets_common': [
        'my_module/static/src/scss/your_reports.scss',
    ],

}

Thank you