Mars will be getting close to the Sun as seen from Earth, an arrangement known as the Mars solar conjunction that happens roughly once in twenty six months. During this time, the corona of the Sun will interfere with communications from Earth, which is why NASA is not going to send any commands to its two Mars rovers and three Mars orbiters during the conjugation. NASA will try to avoid sending signals from 22 July to 1 August.
The precaution is being taken out of an abundance of caution, as the space agency does not want the rovers and orbiters to follow commands based on a corrupted communication. The data from Mars to Earth will continue streaming in during the period though. The data coming in is also expected to get corrupted, which is why the rovers and orbiters have been set up to retransmit the data after the conjugation. The telemetry data will allow NASA to continue to stay updated on the rovers and orbiters during the moratorium.
The rovers will not be moving during the period, but will continue to make observations and transmit the data. The teams handling the rovers are identifying an optimum location to park the rovers during the moratorium The orbiters and rovers will continue to carry out commands sent in advance. All of NASA's active missions on Mars have been through at least one solar conjugation before, and the teams are adequately prepared.