It depends on the context of the sentence...
Michael placed a name-card with each guest's name on it where they should sit.
Lucy eagerly awaited the arrival of her dinner guests.
One should never use an apostrophe for the word that.One should always use an apostrophe for the word that's, meaning that is.
An apostrophe is used in contraction. Example: you will: you'll
no.
No, it's not necessary. Your already shows possession. Use apostrophe after a noun and not a pronoun. Example: That's your money.
No, the word "yours" does not use an apostrophe. It is a possessive pronoun that indicates something belongs to you.
Use the apostrophe right after the letter s: fighters'
Use an apostrophe only (without the s) to the word parents if it indicates possession. Example: parents' house
When it is a possessive, use apostrophe. The waitress's coat was stolen. The waitresses' paychecks were cut.
The apostrophe in the word Billy's means Billy's ownership of something.
If you are indicating possession (Achilles' heal) use an apostrophe at the end of the word. If you are simply stating his name, there is no apostrophe.
If you are just putting "Welcome", you wouldn't use an apostrophe or an "s". If you are putting something like "Welcome guests", then no apostrophe is needed. Apostrophes aren't used to make words plural.
Use an apostrophe after the word actors if it indicates possession. Example: actors' guild