the sentences used on a mail

Hello!^^

Thank you for sending your homework.

Cheers!

Jean

Dear [Name]

Please check the following sentences which use at work for a design modificaton or pointing the defective products.

>> Please check the following sentences, which I use at work for a design modification or pointing out the defective products.

 ↓
print a specified pattern on a shoe lace

>> correct

>> or: Print a specific pattern on a/the shoe lace. 

>> Note: The two sentences are slightly different in meaning.

 change the material of the logo part to another print material.
>> correct

 embroider a specific logo here.
>> correct

 change the color here to the specified color.
>> correct

 As the heel side is a bit dirty, please be careful on a mass production.
>>  As the heel side is a bit dirty, please be careful when mass producing.

 There are many wrinkles on the upper of shoes. put a reinforcement on the back of the toe part.

>> There are many wrinkles at the upper part of the shoes. Put a reinforcement at the back of the toe part.

 I showed the customer a sample made of print fabric, but the print color seems to be different from what they intended.

>> I showed the customer a sample made of print fabric, but the print color seems to be different from what he/she has in mind.

 change the pattern and color again. (Attach pattern)
>> correct

>> change the pattern and the color again.

>> Note: The two sentences are slightly different in meaning.

 Can the color be a little brighter?

>> correct

 Can the color be a little darker?

>> correct