Arduino MKR WIFI 1010 is designed to quickly and easily add Wi-Fi connectivity to any Arduino MKR based application.

The board is composed of three main blocks:

• SAMD21 Cortex-M0+ 32bit Low Power ARM MCU;
• U-BLOX NINA-W10 Series Low Power 2.4GHz IEEE® 802.11 b/g/n Wi-Fi; and
• ECC508 Crypto Authentication. (datasheet)

The USB port of the MKR WIFI 1010 can be used to supply power (5V) to the board.
It has a Li-Po charging circuit that allows the Arduino MKR WIFI 1010 to run on battery power or an external 5 volt source, charging the Li-Po battery while running on external power.
Switching from one source to the other is done automatically.
 

Warning: Unlike most Arduino boards, the MKR WIFI 1010 runs at 3.3V.
The maximum voltage that the I/O pins can tolerate is 3.3V.
Applying voltages higher than 3.3V to any I/O pin could damage the board.
While output to 5V digital devices is possible, bidirectional communication with 5V devices needs proper level shifting.