md5 cracking with rules
I have an md5 hash without salt but I can't make rules to crack it, 
I know my password has 10 chars with 4 digits randomly placed, and I know it's a English word of 6 chars.
I have a wordlist but I can't append 4 digits in it.
If someone can help me I would be thankful.
do you mean 4 digits randomly inserted into the word or appended, its not really clear

stupid 4 digit append would be constructing a rulesset like that

$0000 > password0000
$0001 > password0001
$0002 > password0002

But this can be done simpler by a combinator attack of your wordlist with a second one, you can generate the second list like this

hashcat -a 3 --stdout -1 ?d ?1?1?1?1 > digit.list

inserting randomly 4 digits at 4 places or one into a word is a little more complicated

inserting 4 digits at one position would be generating rules like this
iNX (insert X at N)

i00i00i00i00 > 0000password
i01i00i00i00 > 0001password
i10i10i10i10 > p0000assword
i11i10i10i10 > p0001assword

this example above should be possible to be generated by maskprocessor, see 

inserting one digit at 4 "random" positions would be generating all possibilitys

not sure if this is possible with maskprocessor
Yes it is 4 random digit randomly placed in a word (exemples : artist + 1234 −→ 1ar23t4ist ; august + 9876 −→ augu987st6) thank you