How can I send integer from arduino to another arduino by FS1000A / XY-MK-5V 433Mhz TX/RX Module (WIFI)?
Have a look at the Easy Transfer library.  I haven't used the particular modules you have, however I did successfully use the EasyTransfer library with Ciseco wireless modules.  In essence the EasyTransfer library transmits the data as a structure with the same format on each module.  The structure can contain any data type.