~/Arduino/Blink$ tree
.
├── Blink.ino
└── libraries
    └── ExampleLibrary
        └── MyLib.h

3 directories, 2 files
~/Arduino/Blink$ cat Blink.ino 
#include <MyLib.h>

void setup() {
	libFunction();
}

void loop() {
}
~/Arduino/Blink$ cat libraries/ExampleLibrary/MyLib.h 

void libFunction() {
}

~/Arduino/Blink$ arduino-cli compile -b arduino:avr:uno 
/home/cmaglie/Arduino/Blink/Blink.ino:1:10: fatal error: MyLib.h: No such file or directory
 #include <MyLib.h>
          ^~~~~~~~~
compilation terminated.

Used platform Version Path
arduino:avr   1.8.6   /home/cmaglie/.arduino15/packages/arduino/hardware/avr/1.8.6
Error during build: exit status 1

~/Arduino/Blink$ arduino-cli compile -b arduino:avr:uno 
Sketch uses 444 bytes (1%) of program storage space. Maximum is 32256 bytes.
Global variables use 9 bytes (0%) of dynamic memory, leaving 2039 bytes for local variables. Maximum is 2048 bytes.

Used library   Version Path
ExampleLibrary         /home/cmaglie/Arduino/Blink/libraries/ExampleLibrary

Used platform Version Path
arduino:avr   1.8.6   /home/cmaglie/.arduino15/packages/arduino/hardware/avr/1.8.6