You can create a dashboard that displays the data as you'd like to see in a report and then subscribe to that dashboard on a daily or weekly basis and get a email of the dashboard. There currently isn't a PDF option at this time but Dynatrace is working to expand their "Report" capabilities.
Custom Reports can only be view via dashboards at this point in time. We have crated dashboards to VP's that showcase failure rates, throughput, and response times per their desired scope. They then take a look at that dashboard either daily/weekly/monthly. Same goes for Synthetics, We listed the metrics of synthetics on a dashboard for them and on a monthly basis they pull the Percentages as its shown on the dashboard and supply it in their VP Excel sheets.