Please check the information about coronavirus at the Ministry of Health website.
You can see that countries are divided into groups according to the level of risk (http://www.koronavirus.mzcr.cz/en/list-of-countries-according-to-the-level-of-risk/). The colour indicates the level of risk and also tells you what measures you have to follow after your arrival in the CR.
The most important thing is: before your departure from your home country, you have to fill in the following online form – https://plf.uzis.cz. This duty applies to all people arriving in the CR. We recommend to print out the form and have it ready when crossing the border. Mainly at the Prague airport.
There is also a hot line in English available: +420 974 801 801 (Mo–Th: 8.00–16.00 and Fr: 8.00–12.00)