Which word is better to use? That depends on whether your meaning is restrictive or nonrestrictive.
If the information in your sentence applies to something specific in the sentence, then it is restrictive (it applies to one thing or one group of things). In that case, use “that.”
Example: The umbrellas that are on sale have red tags.
This implies that not all the umbrellas are on sale, only those with the red tags.
If the information in your sentence applies to all things defined in the sentence, then it is nonrestrictive (there are no limits or specifications). In that case, use “which.”
Example: The umbrellas, which are on sale, have red tags.
This implies that all the umbrellas have red tags.
What message are you trying to convey? Are you talking about everything or specific things? Using the right word will send the message you want to send.
Contact editsbymarks.com for help in putting your best word forward from a professional editor.