Every assignment in Phasmophobia has four objectives. Each objective is worth a minimum of $10. You do not have to complete all of the objectives for the assignemnt to be successful, so be careful going after the more unlikely objectives if you have a lot of equipment invested. Losing $2,500 in Equipment for an objective worth $10 is just bad planning, no matter how you look at it.
The first objective for all assignments in Phasmophobia is always to identify the type of ghost by collecting evidence in your journal. This is your most important objective. As long as you complete this one and survive, the assignment will be a success. The types of evidence you're looking for can include three of the following: Freezing Temperatures, EMF Level 5, Ghost Orbs, Fingerprints, Ghost Writing Book, or Spirit Box.
Getting a Photo of the ghost is another objective in Phasmophobia. This one is sometimes very easy, but often isn't worth the trouble. For the most part, if you can't coax the ghost to show itself without angering it, then it's simply not worth the risk. Some ghosts will show themselves easily and often, where others are almost only visible when they are attacking. And if you are trying to get a Photo while it is attacking, your odds of survival are very low and the Photo often doesn't count as a Photo of the ghost for some odd reason. So trying to get a Photo of the ghost during a hunt is usually, but not always, a waste of effort.
You can also get an objective to get a Photo of Dirty Water in a Sink. This objective is quite often a write off in Phasmophobia. If the ghost is in a room with a sink then you have a chance. I won't say a good chance, but a chance. If the ghost is not inhabiting a room with a sink then your odds of getting the event to happen is roughly 0. Standing near a sink and saying 'Give us a sign' may help coax the ghost into performing the event. It is not worth putting much effort into this one.
This is one of the riskier objectives you'll get in Phasmophobia. For this one you will need the ghost to be unhappy with you enough to attack you. What this basically means is anger the ghost and hope it tries to start a hunt in a location with a Crucifix on the ground. The Crucifix will block the ghost from starting a hunt and the objective will be complete. Keep in mind the ghost needs to attempt to hunt you and it must also make the attempt to start the hunt in an area protected by a Crucifix. If the ghost hunts then the Crucifix was in the wrong place: hide or die. A Crucifix in your hand is useless.
You'll need a Thermometer to complete this objective in Phasmophobia. Sweep the location with a Thermometer until you find a room with the required temperature. This should be the room that the ghost is inhabiting. Keep in mind that this objective may take some time. The room temperature may not drop right away. It might never drop either. It is also possible to have a Thermometer bug that will make it impossible.
If you get the ojective to Witness a Ghost Event in Phasmophobia right now, consider it one of those 'if it happens it happens' objectives. There are very few things that qualify. Not even a hunt or watching a member of your team get killed seems to do the trick. If you get lucky enough to have the ghost appear and startle you that may count. Getting a photo of the ghost may also count, but don't hold your breath.
This one is pretty easy. All you have to do is place some Salt in the room the ghost is inhabiting and give it some time. It's always a good idea to bring the maximum amount of Salt you can, which will allow you to cover the room and doorways. Once you have placed the Salt you can wait in the truck if you wish, as the objective will be complete the moment a ghost walks through the salt. Also keep in mind that even a wraith can walk through Salt. The description says 'almost never touches the ground', so therefore, it actually does sometimes.
Once you know what room the ghost is in this one should be easy. Simply place Motion Sensors around the room and wait. You can wait in the truck if you like, it doesn't matter once the sensors have been placed.