Do you mean to find "MCAF" and "MPCAF" as substrings in your data values? if yes, see this:
data have;
input mydata $80.;
datalines;
String with MCAF
String without
String with MPCAF
;
run;
data want;
set have;
where index(mydata,'MCAF') or index(mydata,'MPCAF');
run;