Spying on someone's phone is a crime in most places, and trust is a basic pillar for any relationship. No, we are not going to tell you how to spy on someone's phone, but we do want to help you in case you are being spied on. Your right to privacy is fundamental, so we will explain some basic tips. Remember that if someone has been spying on you without your consent, in most cases you can report it to the authorities.
First of all, you should check if these applications, or others, are installed on your phone in order to erase them. If you have a iOS device, open the App Store, press Updates (it's at the bottom right of the screen), and then select Purchased. If you have an Android, open the Google Play Store, choose Apps, and then select My apps to see all the apps you have installed.
Some of these applications are installed in the system's root folder, so they may not appear in the App Store or the Google Play Store. There are applications that allow you to explore these types of files. If you use Android, here you have a selection of apps to perform that action; if you have an iPhone or other iOS device, you can click here.
If your partner or another person wants to spy on your phone, they will most likely take advantage of you to access it and install hidden applications that will open the doors of your phone's apps (WhatsApp, Facebook, location, etc.). Using complex passwords and changing them from time to time is not a perfect remedy, but it helps to protect your phone. To keep all your passwords at your fingertips, you can use a reliable password manager, such as Dashlane.
Remember to alternate upper and lower case letters, symbols, letters, and numbers to make your passwords more complex. You can use free services such as RandomKeygen to generate complex passwords. If your device uses numerical codes, change them frequently and always use long combinations and avoid those that can easily be associated with you, such as your date of birth. In case you use a pattern to unlock your phone, avoid those logical sequences that can be easily memorized with a simple glance and do not forget to clean your screen. The grease from your fingers leaves a trace and can be used to find out your unlock pattern. If, in addition, your mobile allows you to combine different unlocking methods (biometric readers, unlock pattern, password, etc.), which is even better.